“Acid deposition is a phenomenon resulting from complex reactions between OH, NO2 – Nitrogen dioxide, and SO2. While the natural pH value of rain is lower than 7 (mainly due to dissolved CO2 – Carbon dioxide), the term acid rain refers to precipitation with a pH value less than 5, which occurs in regions with large amounts of anthropogenic pollution. Aerosol and rain are expected to be slightly acidic in the presence of natural sources of SO2 and NO2, such as in tropical rain forests. However, atmospheric pollution”.. More here

“The Earth’s climate has changed throughout history, about 7 cycles in the last 650,000 years with the abrupt end of the last ice age about 7,000 years ago, marking the beginning of the modern climate era and of human civilisation. Most of these climate changes have been attributed to variations in Earth’s orbit modifying the amount of solar energy received at the Earth’s surface. Currently, anthropogenic climate change is receiving much attention, but is leading to controversial political and societal debates, as it would require major changes in our societies…” More here

“The ozone hole, discovered over Antarctica (Farman et al., 1985), is a phenomenon of severe ozone depletion at the altitude between 15-20 km. It occurs in late winter / early spring in presence of polar stratospheric clouds (PSCs), sunlight, strong westerly winds and when the air is isolated from other stratospheric regions. Although located in the stratosphere, it is strongly connected to the troposphere: …” More here

“According to the World Health Organization (WHO), air pollution has become the world’s single biggest environmental health risk, with around 7 million people, or nearly one in eight, deaths in 2012. 3.7 million persons were affected by outdoor pollution from traffic fumes and coal-burning. The results include stroke, heart and lung diseases, and cancers. The main risks are located within the growth of cities and industrial areas, notably in south-east Asia with 2.6 million deaths with continuing deep poverty in rural areas. Rich countries are not spared…” More here